Federal Preemption of State Environmental Law

The United States Constitution establishes a system of dual sovereignty in which both the federal government and the states may make laws. Although not specifically provided for in the Constitution, a universally-recognized aspect of state sovereignty is state police power, which is the power of a state to pass laws that protect and promote the public health, safety, and welfare of its citizens. Although that power is extremely broad, the Constitution contains both specific and general limitations on the power of states to legislate.

An example of a specific restriction is found in Article I, § 8, which provides that "no state shall enter into any treaty." Making treaties and other agreements with foreign governments has been reserved to the federal government, and thus no state could make a treaty with another country even if making such a treaty might very well be within the police power of the state. The general restriction on state action is found in the second clause of Article VI of the Constitution, commonly known as "the Supremacy Clause." It states that "this Constitution, and the laws of the United States which shall be made in pursuance thereof . . . shall be the supreme law of the land." This means that, while states may legislate in areas not specifically carved out by the Constitution or by Congress as the sole province of federal legislation, if a state and Congress pass legislation that is contradictory, the federal legislation will preempt state legislation. In such a case, any legal challenge to a contradictory state law will be upheld on the ground that the state law is unconstitutional for violating the Supremacy Clause.

In certain areas of environmental law, Congress will see fit to completely preempt states from acting. For example, under the Clean Air Act, states may not pass laws that regulate fuel formulations or automotive emissions in order to control pollution because the inevitable variations in standards from one state to another would be overly burdensome to manufacturers. However, despite the power of the federal government to preempt states from acting in the field of environmental law, most federal environmental statutes recognize that the protection of the environment is in principle an appropriate area for the exercise of state police power to protect the health, safety, and welfare of state citizens.

Many environmental statutes are designed to operate predominantly on the state level and allow or require states to establish and implement their own plans to accomplish a federally-mandated objective. Although, as mentioned, the Clean Air Act prevents states from imposing standards on manufacturers of products that may contribute to air pollution, with regard to pollution sources such as factories and power plants, states are required to establish State Implementation Plans (SIPs) that set standards for each pollutant. Although certain minimum requirements are set either by the Clean Air Act or the Environmental Protection Agency, which administers the statute, states have some flexibility in the actual implementation of their SIPs as long as the standards they set are at least as stringent as the minimum federal standards. Another example of state involvement in the implementation of federal law is seen in the Clean Water Act, under which states must sign off on a proposed project that will affect water quality in that state before the federal government issues the required permits and may reject the project if it does not meet the water quality standards determined by the state. Many federal environmental statutes provide funding to states for programs that are designed to carry out the statute's purposes.